1. Technical Field
The present invention relates generally to coaxial cable connectors. More particularly, the present invention relates to a coaxial cable connector insulator and related methodology for effective physical and electrical insulation and improved impedance matching.
2. Related Art
Cable communications have become an increasingly prevalent form of electromagnetic information exchange and coaxial cables are common conduits for transmission of electromagnetic communications. There are several coaxial cable connectors commonly provided to facilitate connection of coaxial cables to each other or to various communications devices. It is important for coaxial cable connectors to insulate cable signals so that cable communications may be exchanged properly.
Typical coaxial cable connector insulators utilize materials and designs which seek to maximize structural and functional efficacy. For example, as depicted in FIGS. 1 and 2, a common insulator 10 is positioned within a typical connector 20 between an outer conductor 50 and an inner conductor 90. The connector 20 has a first end 21 and a second end 22. The portion of the connector 20 extending generally from the insulator 10 to the first end 21 of the connector 20 is a first impedance section 23 of the connector 20. An opposite portion of the connector 20 extending generally from the insulator 10 to the second end 22 of the connector 20 is a second impedance section 24 of the connector 20. Insulators, such as insulator 10, are commonly disposed within the connector 20 to maintain structural concentricity of the relationship between the inner conductor 90 and the outer conductor 50 of the coaxial cable connector 20. Additionally connector insulators are also utilized in matching impedance between portions of the coaxial cable connector, such as between the first impedance section 23 and the second impedance section 24 of the connector 20. Impedance matching is affected by dielectric behavior of insulator materials. The common connector insulator 10 is typically comprised of readily injection moldable thermoplastic, but other known connector insulators are sometimes formed of Teflon® (or PTFE) due to the material's effective dielectric properties and ability to form a good physical barrier, while also lending some structural support to connector components. However, PTFE insulators are generally more costly to manufacture and do not provide optimal structural support. Connector insulators formed of readily injection moldable thermoplastics are cheaper to manufacture than PTFE insulators, because PTFE is not readily moldable and therefore must generally be machined into a desired shape. Thermoplastic insulators provide better structural support, but have less effective dielectric properties than PTFE insulators. Accordingly, common thermoplastic insulator designs have included hollowed out sections to decrease the amount of material forming the insulator, thereby improving dielectric performance. For instance, some common insulators, such as insulator 10 depicted in FIG. 1, comprise a generally ring-like structure having a reentrant cavity 42 extending from an axial end of the insulator 10 and thereby forming a substantially C-shaped cross-section 12. The insulator 10 may have web members 60, which in cross-section view have a generally rectangular-shaped cross-section 62. While the known C-shaped cross-section 12 insulator 10 does enjoy some improved dielectric performance over a solid block ring insulator formed of the same material, the typical disk-like solid mass of radial plastic 14 running orthogonally from the inner axial surface 16 of the insulator to the outer axial surface 18 generates a low unmatched impedance zone that contributes to unwanted signal reflection. Hence, because of the structural deficiencies of PTFE insulators and the dielectric deficiencies of the standard C-shaped cross-section 12 insulators 10, there exists a need for a coaxial cable connector insulator that is cheap and easy to manufacture with good physical properties, better dielectric performance, and improved impedance matching.